08-16-2017, 09:36 PM
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SHASHI KUMAR .K
SHASHI KUMAR .K
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INTRODUCTION
Electrical heating is based on the principle of that when electric current passes through a medium
heat is produced. Let us take the case of solid
material which as resistance R ohms and current
flowing through it is I amps for t seconds than heat
produced in the material will be H=I Rt Joules.
DOMESTIC APPLICATIONOF ELECTRICAL HEATING
Room heater for heating the buildingImmersion heater for water heating
Hot plates for cooking
Geysers
Electric kettles
Electric Iron
Electric oven for baking products
Electric toasters
INDUSTRIAL APPLICATION
Melting of metals
Electric welding
Mould ling of glass for making glass appliances
Baking of insulator
Mould ling of plastic components
Heat treatment of pointed surpasses
Making of plywood.
CLASSIFICATION OF ELECTRICAL HEATING
Power Frequency heating
Resistance heating
Direct Resistance heating
Induction heating
Indirect Resistance heating
induction heating
Arc heating
Direct Arc heating
Indirect Arc heating
High Frequency heating
1. Induction heating
a. Direct Core type
b. Core less type
2. Dielectric heating
RESISTANCE HEATING
This method is based upon the I R loss.
Whenever current is passed through a
resistor material heat is produced because
of I R losses.
1. DIREDCT RESISTANCE HEATING
2. INDIRECT RESISTANCE HEATING
CAUSES OF FAILURE OF HEATING ELEMENTS
Formation of hot spots.
Oxidation
Corrosion
Mechanical failure
DIELECTRIC HEATING
APPLICATION OF DIELECTRIC HEATING
Plywood Industry
Sand Core Baking
Plastic Industry
Tobacco Industry
Bakeries
Electronic Sawing
Dehydration of food
Electro medical application
Book Binding
ADVANTAGES OF ELECTRICAL HEATING OVER OTHER METHOD OF HEATING
Clean and atmosphere
No pollution
Controlled temperature
Localized application
Uniform heating
Highest efficiency of utilization
Cheap furnaces
Mobility of job